1. Make sure they will use only Windows or Mac, not iPhone, iPad or Android device, nor Windows RT.
2. Make sure they have Acrobat Reader or Adobe Reader or Acrobat installed.
3. Make sure they are USING Adobe technology to view, not a browser (except IE or Mac Safari suitably set up). Not Mac Preview or Windows Reader or Edge (which keeps setting itself as default).
4. Make sure that the user has a suitable version of Flash installed, if policies permit (not just the Flash needed by their browser).
Or, give up on a technology now past its peak, and link to a web page with the video instead.
is there anything we can do to make it where it works on most versions of flash?
You must install the right sort of Flash Player (NPAPI I think). There is no substitute. Rrader 10 and below included a built in player.